Implement virtual KJob::doKill in FileTransferJob

This basically allows killing the job from the JobTrakcer
aka Plasma.

kded/filetransferjob.cpp

@@ -201,3 +201,13 @@ void FileTransferJob::sourceFinished()
     emitResult();
 }
 
+bool FileTransferJob::doKill()
+{
+    if (mDestinationJob) {
+        mDestinationJob->close();
+    }
+    if (mOrigin) {
+        mOrigin->close();
+    }
+    return true;
+}

kded/filetransferjob.h

@@ -50,6 +50,8 @@ public Q_SLOTS:
     void sourceFinished();
     void openFinished(KJob*);
 
+protected:
+    virtual bool doKill();
 private:
     void startTransfer();
     QSharedPointer<QIODevice> mOrigin;